It is often desirable to drive a capacitance quickly and accurately to a desired voltage and to maintain that voltage despite sudden load and line changes. This need is particularly acute in the output of power supplies, but also arises in precision applications such as driving the highly-capacitive inputs of some analog-to-digital converters. It is common practice to obtain low instantaneous output impedance using large capacitors. With descending frequency, capacitive reactance increases, and at some band of frequencies one augments the susceptance of the capacitor using a control loop around an amplifier or other gain block. The amplifier is commonly responsive to the difference between a signal representing desired output voltage and actual output voltage. The problem that arises with this classic control loop is that somewhere in the bandpass of the amplifier there exists a peak accompanied by large and abrupt phase changes with frequency. This happens because a pole is formed by the amplifier output impedance and the capacitance being driven. This pole attenuates control loop feedback at higher frequencies where the amplifier still has significant gain. The transient dynamics of the classic control loop often suffer from this problem, and some loops even oscillate unless carefully adjusted. The classic dilemma is that with large output capacitors one can obtain low instantaneous output impedance, but only by compromising the ability of the control loop to respond quickly to line and load changes. This problem is so pervasive that one semiconductor data book, “Amplifiers, Book 1 of 2” of the 2004 Linear Family Databooks, by Linear Technology Corp., of Milpitas, Calif., devotes pages 40, 41 and 42 to a list of approximately 144 amplifiers, called “C-Load OP AMPS”, especially designed for driving capacitive loads. The problem with the classic loop arises from feeding back within the control loop a linear representation of output voltage that mismatches in incremental shape the energy demand of output capacitance in the event of a requirement to respond to change.